U.S. Pat. No. 3,282,875 discloses useful copolymers of fluorovinyl compounds and sulfonated fluorovinyl ethers of the general structure EQU MSO.sub.2 CFR.sub.f CF.sub.2 O(CFYCF.sub.2 O).sub.n CF.dbd.CF.sub.2
where R.sub.f is a radical selected from the class consisting of fluorine and perfluoroalkyl radicals having from 1 to 10 carbon atoms, Y is a radical selected from the class consisting of fluorine and the trifluoromethyl radical, n is an integer of one to three inclusive, and M a radical selected from the class consisting of fluorine, the hydroxyl radical, the amino radical and radicals having the formula -OMe where Me is a radical selected from the class consisting of alkali metals and quaternary ammonium radicals.
Inclusion of a third component chosen from perfluoro alpha-olefins such as hexafluoropropylene or compounds of the type CF.sub.2 .dbd.CFO(CF.sub.2).sub.n CF.sub.3 where n is 0 to 5 is taught as useful when elastromeric properties are desired.
U.S. Pat. No. 4,126,588 teaches a fluorinated cation exchange membrane made of a three component copolymer produced by copolymerizing a fluorovinylpolyether having the formula I ##STR3## wherein .alpha. is 0 to 3; .beta. is 0 to 6; .gamma. is 0 to 4 and either .alpha. or .gamma. is not 0; X, X' and X" respectively represent -F or a C.sub.1-5 perfluoroalkyl group; A represents --CN, --COF, --COOH, --COOR.sub.1, --COOM or --CONR.sub.2 R.sub.3 ; R.sub.1 represents a C.sub.1-10 alkyl group preferably a C.sub.1-3 alkyl group, R.sub.2 and R.sub.3 respectively represents hydrogen atom or a C.sub.1-10 alkyl group; and M represents an alkali metal atom or a quaternary ammonium group, a fluorovinyl compound having the formula II EQU CF.sub.2 .dbd.CF--(O).sub..delta. --(CFY).sub..gamma. --A (II)
wherein .delta. is 0 to 1; .gamma. is 1 to 6; Y represents -F or a C.sub.1-5 perfluoroalkyl group; A is defined in the formula I and a fluorinated olefin having the formula III EQU CF.sub.2 .dbd.CZZ' (III)
wherein Z and Z' respectively represent --H, --Cl, --F or --CF.sub.3.
This patent teaches that copolymers of monomers I and III are low molecular weight and that these polymers, when made having suitable concentrations of the functional group A, have unsuitable mechanical properties. Copolymers made from monomers II and III are higher molecular weight, but have low flexibility and blister when used in chlor-alkali electrolytic cells. These mechanical properties are overcome by forming polymers with monomers I, II, and III.
Japanese Publication No. 1977118597 teaches polymers made by choosing one monomer from each of the three groups ##STR4## where p has a value 2-9, q a value 0-5, and r a value 0-5, EQU CF.sub.2 .dbd.CZZ'
where Z and Z' are fluorine, chlorine, hydrogen, or CF.sub.3, and EQU CF.sub.2 .dbd.CX--OCF.sub.2 CFY--.sub.l (O).sub.m (CFY').sub.n A
where X is F or --CF.sub.3 ; Y and Y' are F, a perfluoro alkyl group of carbon 1-10; and A is one of the following ion exchange groups, --SO.sub.3 H, --COOH, --PO.sub.3 H.sub.2, --.phi.OH (.phi. is an aryl group), or --C(CF.sub.3 OH) or a group which can be replaced by one of these ion exchange groups. In addition, l is an integer 0-3, m is 0 or 1, and n is 0-12. The polymers produced from the above monomers are later crosslinked making use of the iodo substituent. The crosslinking of the polymer can be by any of the well known techniques such as heat, ultraviolet radiation, or ionizing radiation. One example is to heat the polymer to about 250.degree. C. while removing the iodine generated under reduced pressure.
British Pat. No. 1,497,748 teaches a polymer membrane made from (1) a vinyl ether represented by the general formula EQU X(CF.sub.2).sub.n --O--CF.dbd.CF.sub.2
where
n=2-12 PA1 X=CN, COF, COOH, COOR, COOM, or CONR.sub.2 R.sub.3, PA1 R=alkyl group having 1-10 carbon atoms, PA1 R.sub.2 and R.sub.3 =H or R, PA1 M=Na, K, or Cs, and PA1 (2) tetrafluoroethylene, and PA1 (3) R.sub.f --O--CF.dbd.CF.sub.2 PA1 R.sub.f =a perfluorinated alkyl group having 1-3 carbon atoms. PA1 Z and Z'=F or a C.sub.1 10 perfluoroalkyl group, PA1 l'=0-3, PA1 m'=0-12, PA1 n'=0-12, PA1 B=--F, --H, --Cl, --CHF.sub.2 or --CF.sub.3, which have no ion exchangable group or no functional group which can be converted to an ion exchangable group. PA1 R is ##STR6## in which R' is F or perfluoroalkyl of 1 to 10 carbon atoms; Y is F or CF.sub.3 ; m is 1, 2 or 3; n is 0 or 1; X is F, Cl, H, CF.sub.3 ; X' and X are CF.sub.3 --(CF.sub.2).sub.z wherein z is 0-5; the units of formula (1) being present in an amount of from 3-20 mole percent. PA1 a is zero or an integer greater than zero; PA1 b is zero or an integer greater than zero; PA1 c is 0 or 1; PA1 a+b+c.noteq.0; PA1 X is Cl, Br, F, or mixtures thereof when n&gt;1; PA1 n is zero or an integer greater than zero; and, PA1 Rf and Rf' are independently selected from the group consisting of F, Cl, perfluoroalkyl radical and fluochloroalkyl radical; PA1 a' is zero or an integer greater than zero; PA1 b' is zero or an integer greater than zero; PA1 c' is zero or one; PA1 a'+b'+c'.noteq.0; PA1 X' is F, Cl, Br, or mixtures thereof when n'&gt;1; PA1 n' is zero or an integer greater than zero; and PA1 R.sub.f and R.sub.f ' are independently selected from the group consisting of F, Cl, perfluoroalkyl radical and chloroperfluoro alkyl radical; PA1 a is zero or an integer greater than zero; PA1 b is zero or an integer greater than zero; PA1 c is 0 or 1; PA1 a+b+c.noteq.0; PA1 X is Cl, Br, F, or mixtures thereof when n&gt;1; PA1 n is zero or an integer greater than zero; and PA1 R.sub.f and R.sub.f ' are independently selected from the group consisting of F, Cl, perfluoroalkyl radical and fluochloroalkyl radical; and PA1 a' is zero or an integer greater than zero; PA1 b' is zero or an integer greater than zero; PA1 c' is zero or one; PA1 a'+b'+c'.noteq.0; PA1 X' is F, Cl, Br, or mixtures thereof when n'&gt;1; PA1 n' is zero or an integer greater than zero; and PA1 R.sub.f and R.sub.f ' are independently selected from the group consisting of F, Cl perfluoroalkyl radical and chloroperfluoro alkyl radical;
were
British Pat. No. 1,518,387 shows polymers produced from the polymerization of at least three monomers, each selected from one of these groups: